Reactions of alkyl 4-hydroxybut-2-ynoates with arenes under superelectrophilic activation with triflic acid or HUSY zeolite: Alternative propargylation or allenylation of arenes, and synthesis of furan-2-ones
作者:Natalia A. Devleshova、Stanislav V. Lozovskiy、Aleksander V. Vasilyev
DOI:10.1016/j.tet.2019.130517
日期:2019.9
respectively. Reactions of these species with arenes at C4 lead to products of arene propargylation, alternatively, reactions at C2 result in allenylation of arenes, followed by further transformation into furan-2-ones. Using quantum chemical calculations by the DFT method, it has been shown that the reactivity of such propargyl-allenyl cations is mainly explained by orbital factors. Plausible reaction mechanism
烷基-4-芳基的反应(或4,4-二芳基)-4-羟基丁-2- ynoates [氩(H或Ar')(OH)C 4 -C 3 ≡C 2 -CO 2 ALK]与芳烃下三氟甲基磺酸TfOH或HUSY沸石的作用导致形成两种主要化合物:芳基取代的呋喃-2-酮或富电子芳烃的炔丙基化产物。在这些转换键的反应性中间体相应的起始butynoates中,Ar(H或Ar')(的O,O-双质子形式+ OH 2)C 4 -C 3 ≡C 2 - C(= O + H)(OAlk) ,其脱水会产生介晶的炔丙基-烯丙基阳离子Ar(H或Ar')(OH)4 C+ -C 3 ≡C 2 -C(= O + H)(OAlk)↔的Ar(H或Ar')(OH) 4 C = C 3 = 2 Ç + -C(= O + H)(OAlk),在碳C4和C2上分别具有两个亲电中心。这些物质与芳烃在C4的反应会导致芳烃的炔丙基化产物,或者,在C2的反应会